Vitamins B6, B9 (Folate), B12

Our rating
Folate (B9) to boost the effect of anti-depressant medication 1 smiley:  This treatment is promising and may be useful. It has some evidence to support it, but more evidence is needed to be sure it works.
Vitamin B6, Folate (B9) and B12 as a stand-alone treatment Question mark:  This treatment has not been properly researched. It is not possible to say whether it is useful or not.


The rating system

  • 3 smiliesThese treatments are very useful. They are strongly supported as effective by scientific evidence.
  • 2 smiliesThese treatments are useful. They are supported by scientific evidence as effective, but the evidence is not as strong.
  • 1 smileyThese treatments are promising and may be useful. They have some evidence to support them, but more evidence is needed to be sure they work.
  • No smiley On the available evidence, these treatments do not seem to be effective.
  • Question markThese treatments have not been properly researched. It is not possible to say whether they are useful or not.
  • Exclamation MarkSafety or other concerns have been raised for the use of these treatments.

What is it?

Vitamins support normal growth, development, and cell functions. All B vitamins help convert carbohydrates into a source of energy (glucose), and assist in the formation of red blood cells.

How does it work?

It is thought that B vitamins may affect depression in these ways:

  • Some people with depression have been found to have low levels of folate (B9).
  • Vitamin B6, folate (B9) and B12 can change levels of brain chemicals that affect mood (such as serotonin and norepinephrine).
  • SAMe is a natural chemical in the body that may help depression. Folate (B9) and vitamin B12 are involved in the production of SAMe.
  • Vitamin B12 helps maintain the insulation around brain cells. The insulation helps brain cells to communicate.

Is it effective?

There is very little scientific evidence on vitamin B6 and B12 for the treatment of depression. More studies of better quality are needed.

Short-term use of vitamins by themselves do not seem to help reduce depression symptoms. Some studies have found that taking folate (B9) alongside anti-depressant medication can be helpful, and one study found that long-term use of B vitamins reduced the risk of relapse for people who had recovered from depression.

Are there any disadvantages?

Some vitamin supplements can be harmful or ineffective if you take the wrong dose. For example, large doses of Vitamin B6 can cause nerve damage. Talk to your health care professional if you are thinking of taking supplements.

One study reported mania symptoms in a participant who was taking folate (B9) (and antidepressants). No other studies of B vitamins and depression have reported side effects. However, it is not clear whether the studies have investigated negative effects. More research is needed on the possible side effects of B vitamins.

Where do you get it?

Vitamins are present naturally in food. You can buy vitamin supplements in health food shops, supermarkets or from chemists. They usually come in tablet, capsule or powder form. Vitamins may also be given as an injection by a doctor.


Vitamins as a standalone treatment do not appear to be effective at treating depression. Folate (B9) may help boost the effects of anti-depressants.

Key references

  • Almeida OP, Ford AH & Flicker L. Systematic review and meta-analysis of randomized placebo-controlled trials of folate and vitamin B12 for depression. 2015; 27(5), 727-737.
  • Bottiglieri T. Folate, vitamin B12, and neuropsychiatric disorders. Nutrition Reviews. 1996; 54(12), 382-390. 
  • Papakostas GI, Shelton RC, Zajecka JM, Etemad B, Rickels K, Clain A, et al. L-methylfolate as adjunctive therapy for SSRI-resistant major depression: results of two randomized, double-blind, parallel-sequential trials. American Journal of Psychiatry 2012; 169: 1267-74.
  • Taylor MJ, Carney SM, Goodwin GM, Geddes JR. Folate for depressive disorders: systematic review and meta-analysis of randomized controlled trials. Journal of Psychopharmacology 2004; 18: 251-256.

Last reviewed and updated: 1 May 2019